the big, yellow threat, caught on tape. >> announcer: from the global resources of abc news, with terry moran, cynthia mcfadden, bill weir and tonight, juju chang in new york city. this is "nightline," october 25th, 2012. >> good evening, i'm juju chang. tonight, it's a distressing thought. but internet porn may be replacing sex ed for kids in the digital age. a shocking percentage of pre-adolescent children are being exposed to cyber porn. it fills parents of pre-teens like me with dread. and add to that those explicit lyrics in hip hop and suddenly, the facts of life are x-rated. ♪ i can bed your rock >> reporter: it's lil' wayne in "bedrock," makes the vulgar seem normal. listen to winnifred, who is 12 years old. ♪ i can make your bedrock >> reporter: does she understand what she's singing? >> yeah, we did realize how obscene it was, but we did, we got it, we knew what we were saying. when i can reach into my back pocket and basically pull out some porn, it's so easy and you can't really blame a bunch of children for not understanding how to deal with that. >> reporter: she told